Go ahead and attach the alternator output wire to the downstream side of the ammeter, along with the wiring to the ignition switch, light switch, fuse block (if you have one) etc. That way, the ammeter will show a battery charge/discharge indication after the alternator supplies all the current demand by the rest of the vehicle.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!